Finalization and resurrection

A finalizer (~ClassName in C#) runs cleanup code before an object's memory is reclaimed, usually to release a native resource. Finalization changes the collector's job: an unreachable object with a pending finalizer cannot be freed yet, so the GC must queue it, let a dedicated thread run the finalizer, and only reclaim the memory in a later collection.

Resurrection is the side effect: while queued, the object is reachable again (the queue references it), and its finalizer can even store this somewhere reachable, making an object that was found dead permanently live again. The two flavors of weak reference differ exactly here: a short weak reference (WeakReference by default) is cleared as soon as the object is found unreachable, while a resurrection-tracking one (trackResurrection: true, the WeakTrackResurrection handle type) keeps reporting the object until it is truly gone.

Note

Official docs: Finalizers.

OrionGC does not implement finalization yet: finalizers never run, the allocation flags requesting finalization are accepted and ignored, and WeakTrackResurrection handles behave as plain storage. See Handles during marking.